Improvement



I A. F. JOHNSON.

Sewing Machine.-

Patented Jan. 13; 1857.

min a5 a a 6 74 w "UNITED STATES PATENT ()FFICE.

A. F. JOHNSON, or BOSTON, MASSACHUSETTS.

IMPROVEMENT. lN SEWING-MACHINES.

Specification forming part of Letters Patent No. 16.387, dated January13, 1857.

To and whom it may concern:

Be it known that I, A. F. JOHNSON, of Bos ton, in the county of Sufiolkand State of Massachusetts, have invented certain new and usefulImprovements in Sewing-Machines; and I do hereby declare that thefollowing description, taken in connection with the accompanyingdrawings, hereinafter referred to, forms a full and exact specificationof the same,wherein I have set forth the nature and principles of mysaid improvements, by which my invention may be distinguished fromothers of asimilar class, together with such parts as I claim and desireto have secured to me by Letters Patent.

The figures of the accompanying plate of drawings represent myimprovements.

Figure 1 is a transverse vertical section of my improved sewing-machine.Fig. 2 is a longitudinal vertical section of the same, taken through thepressure-bar. Fig. 3 isa similar section taken through the needle-arm.Figs. 4 and 5 are detail views to. be hereinafter referred to.

My improvement consists in adjusting the I position of the hook withregard to that of the needle, so that it shall take the loop properlyfrom the needle by means of an eccentric headed screw, the hook beingalso actuated by an adjustable set-screw for the needle to take the loopfrom the hook also, in a pivoted pressure-bar,by which the pressure uponthe cloth can be adjusted for the different thickness and quality ofgoods.

a a a a in the drawings represent the supporting frame-work of themachine.

b bis a fixed shaft having but one bearing, upon which are arrangedloosely the cams c d and drivingpulley e. The loop-hook f is attached toa sliding bar, actuated by a stud, h,.traveling in the grooved cam (l.The feeding-bar h h is attached by a pivot-j oint to the rockershaft iz, actuated by a roller or stud, k, traveling on the periphery of thecam c. A spiral spring, I, retracts the rock er-shaft i 43, so as togive the downward motion to the feeding-bar.

m m, Fig. 3, is a U-shaped needlearm turning on a pivot, n, at its bend.The lower bar of this needle-arm has a long slotted groove, 0 0, formedin it, in which works a stud, p, placed ecoentrically in the end face ofthe main driving-pulley c.

From the foregoing description it will be seen that by arranging thecams and driving-pulley loosely upon a fixed shaft having but onebearing I am enabled to drive the needle-arm by the eccentric stud inthe driving-pulley working in the Slot of the said needle-ar1n, whichcould not be effected by the ordinary arrangement of the main shaft anddriving machinery insewing-maehines, as in other machines the main shafthas rotated with the operating-cams and driving-pulley, and has requiredtwo end bearings, which would render it impossible to impart thenecessary motions to the needle-arm by the means employed in my machine.The advantage of driving the needle-arm by the eccentric stud working inthe slotted end of the needle-arm will readilybe apparent, as a quickermotion is obtained thereby, while the needle is operated faster at thedesired ,time,which is when the stud is nearest the pivot of theneedle-arm and when the needle is descending. The loop-hook f isadjusted so as to take the loop properly from the needle by means of theeccentric headed screw q, Figs. 4 and 5,whereby the hook can be set andretained in any position with regard to the needle, whereas with outthis means of setting up the hook it would .not,when out of adj ustment,take the loop properly from the needle. The needle is made to take theloop properly from the hook by means of an adjustable screw, 1', againstwhich the hook abuts during the backward motion of its sliding bar 9,thereby setting the hook in the right position for the needle to takeits loop.

8 8, Figs. 1 and 2, represent the pressure-bar turning on a pivot at tand acted upon by a bent spring, it. Through the end of the pressure-bar is inserted a bent arm, 1; c, Fig. 1, against which thecloth-feeding bar h h abuts. The bent arm 11 o is held in thepressure-bar by means of a set-screw, w, in such a manner as to beraised or lowered at pleasure,which adj ustment can be readily effected,from the fact that the pressure-bar s 8 turns on a pivot. By thisarrangement of the adjustable bent arm 1: rand pivoted pressure-bar, aneasy adjustment can be made for every thickness of goods, while it willalso be observed that more or less press ure can be obtained fordifferent qualities of goods, according as the bent arm 12 o is raisedor lowered in the pressure-bar.

The needle w is inserted in the end of the needle-arm m m, which issplit for the purpose, the two sides being held together by a screw andnut. The advantage of this mode of holding the needle consists inkeeping it always in its true center line, as both sides of the splitneedle-arm will grip the needle equally and keep it in its properposition.

Having thus described my improvements, I

' do not claim the peculiar construction and arrangement of themechanism herein described for driving and operating the machine, as Iintend to make it subject-matter of another application for patent, andI Wish to be understood that I claim neither the set-screw nor acircular plate or cylindrical body rotating upon eccentric pivots as newmeans for adjustment; but

What I claim as my invention, and desire to secure by Letters Patent, is

Combining the hook,when furnished with a lever or arm, as described,with the eccentric A. F. JOHNSON.

\Vitnesses:

EZRA LINCOLN, JOSEPH GAVETT.

